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Cuvier's dictum
, ''Mosasaurus, and the mastodon.]] "Cuvier's rash dictum", also called simply "Cuvier's dictum" or the "rash dictum," was a statement made by comparative anatomist and pioneering palaeontologist Georges Cuvier (23 August 1769 – 13 May 1832) in his introduction to Recherches sur les ossemens fossiles (1812), declaring it unlikely that any large animal remained undiscovered. In the usage of the time, "quadruped" usually referred to mammals, not any four-footed animals, and Bernard Heuvelmans points out that several animals listed by Cuvier to try and prove his dictum weighed only one or two kilos: so "large quadruped" here means almost any mammal down to the size of a platypus or flying phalanger. Although Cuvier conceded that some "unknown quadrupeds" might exist in the interior of unexplored continents, given that traveller's cannot easily traverse such inaccessible regions, he thought even this was unlikely, as, according to him, any big animals in the interior would be likely to follow rivers to the coast. He also criticised the idea that any quadrupeds known only from fossils would ever be discovered alive, particularly "megatheriums and mastodons". In making his dictum, Heuvelmans believed that Cuvier may have been "apprehensive ... at the thought of seeing zoological discoveries in the domain of present fauna undermine the paleontological edifice which he had so laboriously built up in the course of a long and brilliant career". Cuvier's opinion was soon proven wrong - the Malayan tapir was discovered only a few years afterwards, and more discoveries followed through the 19th Century - but Bernard Heuvelmans, who first referred to Cuvier's declaration as his "rash dictum," believed that Cuvier's influence led to most later zoologists accepting his opinion, and refusing to consider the possibility of large undescribed animals, with obvious consequences for cryptozoology. Just as Cuvier, in an attempt to prove that large animals never go unnoticed, listed a number of large quadrupeds which had always been known to ancient scholars, Heuvelmans began On the Track of Unknown Animals (1955) by recounting several of the large quadrupeds which had been discovered since Cuvier's dictum, including the Malayan tapir, the pygmy hippopotamus, the mountain gorilla, the giant panda, the okapi, the giant forest hog, and the Komodo dragon, among others. According to Heuvelmans, Cuvier had already been "contradicted by events ninety times" before his death, yet in the much later sixth edition of his work Treatise on the Revolutions of the Surface of the Globe," he admits only the discovery of the Malayan tapir. In fact, 171 "large quadrupeds" were discovered between 1814 and 1847, including "several rhinoceroses, two horses, buffaloes, stags, enormous antelopes, a hippopotamus, whild boars, bears and anthropoid apes". By Heuvelmans estimation in 1990, no less that 334 "large quadrupeds" had been described after Cuvier made his "rash dictum". Although few if any zoologists or palaeontologists have specifically invoked Cuvier's declaration to argue against cryptozoology in recent years, similar predictions have been made, including by Charles Anderson in 1934 and George Gaylord Simpson (making an "attack" on cryptozoology) in 1984. In debunking Cuvier's dictum, Heuvelmans was not simply criticising a man who had been dead for a century, but arguing against the basic substance of Cuvier's assertion - that no large quadrupeds remain to be discovered - which has been repeated many times since, despite being proven false in the previous instance each time. Notes and references Category:Cryptozoological terms